// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_FILEWRITESTREAM_H_
#define RAPIDJSON_FILEWRITESTREAM_H_

#include "stream.h"
#include <cstdio>

#ifdef __clang__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(unreachable-code)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Wrapper of C file stream for output using fwrite().
/*!
    \note implements Stream concept
*/
class FileWriteStream
{
  public:
    typedef char Ch;    //!< Character type. Only support char.

    FileWriteStream(std::FILE *fp, char *buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferEnd_(buffer + bufferSize), current_(buffer_)
    {
      RAPIDJSON_ASSERT(fp_ != 0);
    }

    void Put(char c)
    {
      if (current_ >= bufferEnd_)
        Flush();

      *current_++ = c;
    }

    void PutN(char c, size_t n)
    {
      size_t avail = static_cast<size_t>(bufferEnd_ - current_);
      while (n > avail)
        {
          std::memset(current_, c, avail);
          current_ += avail;
          Flush();
          n -= avail;
          avail = static_cast<size_t>(bufferEnd_ - current_);
        }

      if (n > 0)
        {
          std::memset(current_, c, n);
          current_ += n;
        }
    }

    void Flush()
    {
      if (current_ != buffer_)
        {
          size_t result = std::fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
          if (result < static_cast<size_t>(current_ - buffer_))
            {
              // failure deliberately ignored at this time
              // added to avoid warn_unused_result build errors
            }
          current_ = buffer_;
        }
    }

    // Not implemented
    char Peek() const
    {
      RAPIDJSON_ASSERT(false);
      return 0;
    }
    char Take()
    {
      RAPIDJSON_ASSERT(false);
      return 0;
    }
    size_t Tell() const
    {
      RAPIDJSON_ASSERT(false);
      return 0;
    }
    char *PutBegin()
    {
      RAPIDJSON_ASSERT(false);
      return 0;
    }
    size_t PutEnd(char *)
    {
      RAPIDJSON_ASSERT(false);
      return 0;
    }

  private:
    // Prohibit copy constructor & assignment operator.
    FileWriteStream(const FileWriteStream &);
    FileWriteStream &operator=(const FileWriteStream &);

    std::FILE *fp_;
    char *buffer_;
    char *bufferEnd_;
    char *current_;
};

//! Implement specialized version of PutN() with memset() for better performance.
template<>
inline void PutN(FileWriteStream &stream, char c, size_t n)
{
  stream.PutN(c, n);
}

RAPIDJSON_NAMESPACE_END

#ifdef __clang__
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_FILESTREAM_H_
